I want to imitate Photoshop layer 'soft light' blending in iOS

In Photoshop a layer can be blended with a layer below it using many different ways, ie Normal, Dissolve, Darken, Soft Light, etc. 开发者_如何学运维 I would like to duplicate this effect programmatically in iOS using the core graphics api. Any ideas?

You can't apply different blending modes between CALayers (at least, on iOS), but if you're implementing -drawRect: or otherwise creating an image, you can certainly use soft light blending with the kCGBlendModeSoftLight CoreGraphics blend mode.

There is an example of layer blending in iOS using Core Graphics in the project I just posted here: https://github.com/esilverberg/ios-image-filters

I only implemented overlay blending so far.